Some compressors (e.g., scroll compressors) include a driving shaft configured to drive a compression mechanism and a slide bearing supporting the driving shaft for allowing the driving shaft to slide therealong. In the well-known compressors, a lubricating oil is configured to be supplied to the sliding surfaces of the driving shaft and the slide bearing for reducing friction to be produced therebetween.
In same cases, however, the lubricating oil supplied to the sliding surfaces leaks from the bottom ends of the sliding surfaces. Further, the leaked lubricating oil is partially discharged out of the compressor together with a refrigerant. When a large quantity of the lubricating oil leaks out of the compressor, this results in reduction in a quantity of the lubricating oil contained in the compressor and troubles of the compressor. For example, leakage of the lubricating oil results in a large friction between the driving shaft and the slide bearing. Therefore, the driving shaft and the slide bearing are both abraded because of the friction produced therebetween.
In view of the drawback, the following compressor-related technology has been proposed. Specifically, a compressor houses a circulation path in the interior thereof for circulating the lubricating oil. A driving shaft includes an annular groove circumferentially extended thereon about a rotation axis thereof. A fixation member is configured to fix the slide bearing and includes an oil path. The oil path allows the lubricating oil, accumulated in the annular groove, to flow to the circulation path. For example, Japanese Laid-open Patent Publication No. 2003-293954 describes the technology.
The aforementioned technology results in reduction in oil-film pressure at the annular groove. The lubricating oil on the sliding surfaces thereby flows into the annular groove. The lubricating oil in the annular groove easily flows to the circulation path through the oil path.